Martensitic transformation (MT) and properties of anelasticity have been investigated. The calculation for the figures of central Bain's lattice deformation caused by MT in alloys of the system Ni50Ti50-xZrx have been accomplished. It was establish that substitution titanium for zirconium from 1 to 20 at.% keeps up the initial B2 structure leading to the formation of uninterrupted range of solid solution. The present system undergoes B2→B19' MT on cooling. The characteristics of MT have been determined. The regularities of anelastic behaviour for this system also have been determined. After the calculation of tensor of deformation in basis of initial crystal lattice it was established that the resource of deformation amounts to 12% in these alloys. As it was shown by the experimental investigations of anelasticity properties, shape memory effect (SME) is realising completely in these alloys.